Tax Filing Extensions (Form 4868)

A tax extension gives you more time to file your return. It does not give you more time to pay. That single point causes most of the problems people have with extensions, so this guide starts there and then walks through how to request one, what it costs and what to do if you have already missed the extended deadline.

What an extension does and does not do

An extension to file avoids the failure-to-file penalty as long as you request it by the original due date and file by the extended date. It does not extend the time to pay. If you owe tax for 2025 and did not pay by April 15, 2026, interest ran from that date, and a failure-to-pay penalty of 0.5% of the unpaid tax applies for each month or part of a month. You should estimate your tax as well as you can and pay at least that amount with the extension request.

By comparison, the failure-to-file penalty is far larger: 5% of the unpaid tax for each month or part of a month a return is late, up to a maximum of 25%. For returns due after December 31, 2025, the minimum penalty for a return more than 60 days late is the smaller of $525 or 100% of the tax due. See failure-to-file penalty and failure-to-pay penalty.

How to request an extension

The IRS lists three ways to get the automatic six-month extension:

1. Pay electronically and check the extension box. Use IRS Direct Pay, your IRS online account, EFTPS, a debit or credit card or a digital wallet and indicate the payment is for an extension. You get a confirmation number and do not need to file a separate form.
2. E-file Form 4868, Application for Automatic Extension of Time to File U.S. Individual Income Tax Return. You will usually need your prior year's AGI to verify your identity. The IRS says Free File providers may offer the form at no cost and that there is no income limit for extensions.
3. Mail a paper Form 4868. Fiscal-year taxpayers can request an extension only on paper.

You do not need to give a reason. You need to request the extension by the original due date.

Example: Jordan estimates his 2025 tax at $13,000 and has $9,000 withheld. By April 15, 2026 he pays the missing $4,000 electronically and checks the extension box. He files on September 20, 2026, and his actual tax turns out to be $13,600, so he pays $600 with the return. Interest and the 0.5% monthly penalty apply only to that $600, counted from April 15, 2026, and not to the whole balance.

People outside the United States

U.S. citizens and resident aliens who are living outside the U.S. and Puerto Rico, or serving in the military outside those places, on the original due date get an automatic two-month extension, generally to June 15, without filing anything. Attach a statement to the return that explains which situation applies. Interest still runs on tax unpaid after April. You can get four more months (six in total) by filing Form 4868 and checking the box that applies to taxpayers abroad. See international tax services.

Taxpayers in federally declared disaster areas, and military members in combat zones, may get additional time. The IRS announces relief for each disaster on its website.

If the extended deadline has passed

For 2025 returns, the extended deadline was October 15, 2026. If you did not file by then, file as soon as possible. The failure-to-file penalty grows each month, and filing sooner stops it from growing. If you are owed a refund, there is usually no penalty, but you generally must file within three years of the original due date to get the refund. See late filing when you are owed a refund. If penalties have been charged, you may be able to ask for relief such as first-time penalty abatement. Several years of missing returns are covered in unfiled tax returns.

Things to know before you extend

• An extension does not extend the deadline for estimated payments or for claiming certain items that depend on dates, such as some retirement contributions tied to the filing deadline. For IRA contributions, the deadline is the original filing date, not the extended date. See IRA and 401(k) contributions.
• If the Social Security number or ITIN you need for a credit has not been issued by the due date, an extension adds time for the number to arrive. For the child tax credit and the new Social Security number rules, the number must be issued by the due date including extensions.
• Late or missing forms, a K-1 that has not arrived or a complex return are all common reasons to extend. Filing the best return you can is better than filing one with guessed numbers.

Illinois

Illinois grants an automatic six-month extension to file the state return. As with the federal system, it does not extend the time to pay. If you expect to owe Illinois tax, the Illinois Department of Revenue says to use Form IL-505-I to make the payment and avoid penalty and interest. See our Illinois guide.

How we can help

We can calculate a safe estimate of what you owe before the deadline, file the extension, and prepare the return when your documents are ready. If a deadline has already passed, we can help you file and review options for penalty relief. See individual tax preparation and our tax calendar, or contact us.

Frequently asked questions

General information only, not tax, legal or accounting advice for your situation. Rules, limits and deadlines change; confirm the current rules with the official source or a qualified professional before you act. Reading this page does not create a professional relationship with CPA Tax Payroll and Accounting Corp.